11 ideas
| 8083 | Boole applied normal algebra to logic, aiming at an algebra of thought [Boole, by Devlin] |
| Full Idea: Boole proposed to use the entire apparatus of a school algebra class, with operations such as addition and multiplication, methods to solve equations, and the like, to produce an algebra of thought. | |
| From: report of George Boole (The Laws of Thought [1854]) by Keith Devlin - Goodbye Descartes Ch.3 | |
| A reaction: The Stoics didn’t use any algebraic notation for their study of propositions, so Boole's idea launched full blown propositional logic, and the rest of modern logic followed. Nice one. |
| 7727 | Boole's notation can represent syllogisms and propositional arguments, but not both at once [Boole, by Weiner] |
| Full Idea: Boole introduced a new symbolic notation in which it was possible to represent both syllogisms and propositional arguments, ...but not both at once. | |
| From: report of George Boole (The Laws of Thought [1854], Ch.3) by Joan Weiner - Frege | |
| A reaction: How important is the development of symbolic notations for the advancement of civilisations? Is there a perfect notation, as used in logical heaven? |
| 8686 | Boole made logic more mathematical, with algebra, quantifiers and probability [Boole, by Friend] |
| Full Idea: Boole (followed by Frege) began to turn logic from a branch of philosophy into a branch of mathematics. He brought an algebraic approach to propositions, and introduced the notion of a quantifier and a type of probabilistic reasoning. | |
| From: report of George Boole (The Laws of Thought [1854], 3.2) by Michèle Friend - Introducing the Philosophy of Mathematics | |
| A reaction: The result was that logic not only became more mathematical, but also more specialised. We now have two types of philosopher, those steeped in mathematical logic and the rest. They don't always sing from the same songsheet. |
| 22277 | Boole's method was axiomatic, achieving economy, plus multiple interpretations [Boole, by Potter] |
| Full Idea: Boole's work was an early example of the axiomatic method, whereby intellectual economy is achieved by studying a set of axioms in which the primitive terms have multiple interpretations. | |
| From: report of George Boole (The Laws of Thought [1854]) by Michael Potter - The Rise of Analytic Philosophy 1879-1930 02 'Boole' | |
| A reaction: Unclear about this. I suppose the axioms are just syntactic, and a range of semantic interpretations can be applied. Are De Morgan's Laws interpretations, or implications of the syntactic axioms? The latter, I think. |
| 3785 | You can't separate acts from the people performing them [Glover] |
| Full Idea: A mistake of consequentialists is to treat actions as though they can somehow be isolated from the people performing them. | |
| From: Jonathan Glover (Introductions to Utilitarianism and its Critics [1990], Pt Five) | |
| A reaction: I agree. The weather produces consequences. Morality is about people. Crocodiles, for example, are exempt. |
| 3786 | Aggression in defence may be beneficial but morally corrupting [Glover] |
| Full Idea: Forming the intention to use nuclear retaliation if attacked may both be the best way to avoid the catastrophe of nuclear war and at the same time be morally corrupting. | |
| From: Jonathan Glover (Introductions to Utilitarianism and its Critics [1990], Pt Five) | |
| A reaction: A famous moment in 2017 when Jeremy Corbyn refused to say he would be willing to use the weapons, if elected. It would be hard to sustain a determination to do it, and then reject it at the crucial moment. |
| 3784 | Duty prohibits some acts, whatever their consequences [Glover] |
| Full Idea: The deontological view is that some acts are absolutely prohibited, regardless of consequences. | |
| From: Jonathan Glover (Introductions to Utilitarianism and its Critics [1990], Pt Five) |
| 3782 | Satisfaction of desires is not at all the same as achieving happiness [Glover, by PG] |
| Full Idea: Objections to utilitarianism as maximisation of preferences: faded past desires or the desires of the dead; obtaining desires and happiness are different; fewer desires are easier to satisfy; pain is good if it can be removed. | |
| From: report of Jonathan Glover (Introductions to Utilitarianism and its Critics [1990], Pt Two) by PG - Db (ideas) |
| 3787 | Rule-utilitarianism is either act-utilitarianism, or not really utilitarian [Glover] |
| Full Idea: Rule-utilitarianism seems either to collapse into act-utilitarianism, or else it is only partly utilitarian. | |
| From: Jonathan Glover (Introductions to Utilitarianism and its Critics [1990], Pt Six) |
| 3783 | How can utilitarianism decide the ideal population size? [Glover] |
| Full Idea: There are deep problems for utilitarianism in trying to work out what the ideal population size would be. | |
| From: Jonathan Glover (Introductions to Utilitarianism and its Critics [1990], Pt Four) |
| 19399 | Prime matter is nothing when it is at rest [Leibniz] |
| Full Idea: Primary matter is nothing if considered at rest. | |
| From: Gottfried Leibniz (Aristotle and Descartes on Matter [1671], p.90) | |
| A reaction: This goes with Leibniz's Idea 13393, that activity is the hallmark of existence. No one seems to have been able to make good sense of prime matter, and it plays little role in Aristotle's writings. |